1. Field of the Invention
The invention relates to the filter chamber having a plurality of annular filter elements located therein for filtering liquids.
2. Description of the Prior Art
Hollow cylindrical filter elements have been used for filtering liquids such as water, acids, etc. to remove waster materials therefrom.
The lengths of these filter elements obtained commercially vary for example as much as 1/2 of an inch.
Known prior art devices have employed a plurality of these elements in a filter chamber. Some of these prior art devices use rods secured to a lower manifold and which rods extend through the filter elements. Nuts are provided with an annular knife edge that are screwed to the upper ends of the rods, and which forms seals with the upper ends of the filter elements. The use of rods which extend through the filter elements results in a large pressure drop between the inlet and outlet which requires a large pump to pump the liquid through the filter device. Other known prior art devices use individual plastic springs for urging closure means with annular knife edges against the upper ends of the annular filters for closing the top openings thereof. These springs, however, tend to break and are difficult to replace.
U.S. Pat. Nos. 1,941,895, 4,052,317, 4,725,323, 4,728,421, 5,173,186, and 5,770,066 discloses other prior art filter apparatus.